This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 1 | 10 |
| 2 | 100 |
| 3 | 390 |
| 4 | 1950 |
| 5 | 9072 |
| 6 | 43498 |
| 7 | 206514 |
| 8 | 982940 |
| 9 | 4672690 |
| 10 | 22223478 |
| 11 | 105684192 |
| 12 | 502611290 |
| 13 | 2390250122 |
| 14 | 11367287780 |
| 15 | 54059152686 |
| 16 | 257088257194 |
| 17 | 1222630168560 |
| 18 | 5814441801566 |
| 19 | 27651641179470 |
| 20 | 131502438430740 |
| 21 | 625383900547134 |